DISCUSSION
The incidence of
dextrocardia with situs inversus totalis is 1/10,0000–50,000 births.(6)
In such patients, the IVC might be interrupted or stenotic in 8-18% of
patients, with azygos continuation present in only 0,6% of
cases.7 Unless severe concomitant congenital defects
occur, patients with SID showed life expectancy similar to that of the
general population.8 In literature only few case
reports described ablation strategies in this specific subset of
patients, in which percutaneous PVs isolation can be extremely
challenging. The major limitations are considered: small calibre of the
entrance vessel, often complicated by tortuosity especially at the level
of the azygos vein;9 difficulty in obtaining
trans-septal puncture; limited manoeuvrability of the ablation/mapping
system.7 For these reasons, “unconventional methods”
were explored and described in literature:10,11 so
far, three different PA approaches have been reported: trans-septal
puncture via trans‐jugular approach through the SVC9;
transaortic retrograde approach10 and percutaneous
transhepatic vein approach.11
Trans-septal puncture via
internal jugular/subclavian vein and SVC was described by Masumoto et
al.9 PVs isolation was effectively performed under 3D
navigation system. However, the procedure was reported as extremely long
despite authors simplified the procedure by omitting
electrophysiological mapping of the LA (over 360 minutes of procedural
time with more than 60 minutes of PVI time). Major concerns raised
mainly while performing the trans-septal puncture with a procedure
generally defined as “not smooth”. Of note, authors avoided to
approaching the IVC because of the tortuosity.9
An intriguing trans-aortic
solution was reported by Okajima and colleagues 10 in
this specific subset of patients. Via the left femoral artery authors
gained access to the LA in a retrograde fashion and under magnetic
navigation system. However, authors were unable to perform a complete
isolation of the four PVs: the right inferior PV isolation was aborted
since the ablation catheter repeatedly dropped into the left ventricle
because of an unfavourable angle and short distance between mitral
annulus and PV orifice. Moreover, in order to simplify a such complex
procedure, authors avoided to evaluate entrance/exit block as well as
the electro-anatomical mapping. 9,10
A percutaneous trans-hepatic
vein approach was described by Tandon et al.11 in a
patient with dextrocardia and IVC continuation in the azygos vein. LA
access was gained via hepatic vein puncture under ultrasound guidance
and fluoroscopy. The procedure was reported as safe, however, only
addressed the LAA. 11
Non-invasive percutaneous solutions provided a stable restoration of the
sinus rhythm, however they were reported as particularly challenging. In
most instances, the major drawbacks were the necessity to use different
types of catheters, the complex catheter guidance and manoeuvrability,
thus leading to exceedingly long and often incomplete procedures.
Surgical thoracoscopic AF ablation had the advantage of a direct vision
of the complex anatomy of the patient, allowing the surgeons to promptly
recognize cardiac structures despite the complete SID. Effective lesions
were safely performed and confirmed by testing the presence of the exit
block, thus without affecting the completeness of the ablation lesion
set and the procedural time. Moreover, the LAA was successfully excluded
by epicardial access with no additional risk.
CONCLUSION In conclusion, patients with complex anatomy should be carefully
evaluated with a multidisciplinary approach in specialistic facilities
with a wide expertise in minimally invasive arrhythmia surgery. A
patient-tailored approach was guaranteed once risks and benefits of the
surgical procedure over percutaneous strategy were wisely balanced, thus
providing the best option in terms of safety, efficacy and patient
satisfaction.